Hot melt adhesive applicator



Aug. 29, 1967 A. R. NUGARUS 3,338,2ll

HOT MELT ADHESIVE APPLICATOR Filed June 25, 1965 5 Sheet's--SheerI 1 FIG! E I ,H /35'I l HH Il HH! NVENTOR" ff V ANTHO YRNUGARUS ATT'Y 5 Sheets-Sheet 2 FGZ Aug. 29, 1967 Filed June 25, 1965 FIGB ATT'Y Aug. 29, 1967 A. R. NUGARUS 3,338,2H

HOT MELT ADHESIVE APPLICATOR 3 Sheets-Sheet 3 Filed June 25, 1965 I INVENTOR; ANTHQNY R. NUGARUS FIGB / MY'W ATTY United States Patent Office 3,338,211' Patented Aug'. 29, 1967 3,338,211 HOT MELT ADHESIVE APPLICATOR Anthony R. Nugarus, Chicago, Ill., assigner to Crompton & Knowles Corporation, Worcester, Mass., a corporation of Massachusetts Filed June 25, 1965, Ser. No. 467,047 8 Claims. (Cl. 118-261) ABSTRACT OF THE DISCLOSURE Summary of the invention This invention relates in general to a hot melt adhesive applicator for applying hot melt adhesives and the like to carton flaps prior to closing of the aps so that the aps Will be secured When in closed position, and more particularly to a hot melt adhesive applicator that is capable of applying a defined amount of material to carton aps.

The applicator of the present invention includes a tank or box for holding a supply of hot melt adhesive. Heating elements are provided to maintain the tank and adhesive therein at 'a suitable applying temperature, wherein the adhesive is molten at elevated temperatures and congeals or hardens at lower temperatures. A transfer or application roller is rotatably mounted on the tank so that a part is immersed in the adhesive and another part extends from the tank into the application area. The transfer or application roller includes opposed radially extending faces and a peripheral axially extending face, the latter of which serves to transfer the adhesive to the carton aps by engaging against the aps with a supply of adhesive thereon. An adjustable doctor blade coacts with the application edge of the roller to control the thickness of material thereon and to be applied to the carton aps. Scrapers are provided for the radial faces of the application roller to prevent build up of material thereon. The shaft mounting the application roller is arranged at an angle relative to the vertical. A protective coupling is employed between the application roller shaft and the drive therefor to protect the parts of the applicator if an obstruction is met by the application roller.

It is therefore an object of the present invention to provide a new and improved hot melt adhesive applicator for applying hot melt adhesives and `the like to carton flaps.

Another object of this invention is in the provision lof a hot melt adhesive applicator that can operate eiciently at any angle for applying hot melt adhesives to carton aps.

Still another object of this invention resides in the provision of a hot melt adhesive applicator that is inexpensive to manufacture and easy to disassemble for cleaning purposes.

A further object of this invention is to provide a hot melt adhesive applicator that can -be quickly and easily adjusted to vary the thickness of material -to be coated onto carton aps and the like.

Other objects, features and advantages of the invention will be -apparent from the following detailed disclosure, taken in conjunction with the accompanying sheets of drawings, wherein like reference numerals refer to like parts, in which:

FIG. 1 is a perspective view of a hot melt adhesive applicator according to the invention as it would be employed for applying a coating of hot melt adhesive to carton flaps, and illustrating in phantom the use of a second applicator;

FIG. 2 is a sectional view taken substantially along line 2 2 of FIG. 1, illustrating some parts broken away and other parts in phantom for purposes of clarity;

FIG. 3 is a view of the applicator roller, taken substantially along line 3 3 of FIG. 2 and looking in the direction of the arrows;

iFIG. 4 is a sectional view taken substantially along line 4 4 of FIG. 3;

FIG. 5 is a fragmentary detailed sectional View taken substantially along line 5 5 of FIG. 4 and showing some parts in elevation for purposes of clarity;

FIG. 6 is a sectional view taken through the application roller and substantially along line 6 6 of FIG. 5;

FIG. 7 is a top plan view of the adjusting mechanism for the doctor blade employed in the applicator of the present invention; and

FIG. 8 is ya prespective view, somewhat fragmentary, and illustrating the application roller as associated with the doctor blade and Scrapers.

Referring now to the drawings, and particularly to FIG. l, the applicator of the present invention is generally indicated by the numeral 10 and illustrated as it would be employed to apply a coating of hot melt adhesive to a flap 11 of a carton 12, wherein the cartons would be successively delivered past the applicator. The opposite ap 13 could be suitably coated with an `adhesive by a similar applicator 14 arranged at a position opposite the applicator 10. Any suitable means such as a conveyor may be ernployed for carrying the cartons by the applicators. While the invention is illustrated as applying a hot melt adhesive to a carton, it should be appreciated that it could be employed for applying an adhesive to other types of containers, such as a bag or the like, and further the applicator could be employed for coating other articles with a material other than an adhesive.

The applicator includes in general a tank or box 15 rotatably supporting an application or transfer roller 16 that coacts with a combination doctor and scraper unit 17 for applying a coating of predetermined thickness to a carton flap.

The tank 15 includes opposite side walls 18 and 19, a rear wall 20, a bottom wall 21, and a front wall 22. The opposite side walls 18 and 19 are upstanding and parallel while the rear wall 20 extends normal to the side walls and is also'upstanding. The forward wall 22 includes a lower section 23 that is inclined from the bottom wall 21, and an upper section 24 that is inclined from the lower section 23, The rear wall 20 is open adjacent the side 19 to a loading chamber 25 defined by opposite parallel walls 26 and 27 and an end wall 28. The tank is generally open upwardly and the loading chamber 25 is open to permit the reloading of hot melt adhesive into 4the tank 15 and so that the adhesive ows into the immersion chamber 29. In order to maintain the hot melt adhesive in molten state for application purposes, a plurality of heating element chambers 30 and a thermostatic element chamber 31 are provided in the bottom wall 21 of the tank for respectively receiving electrical heating elements 32 and a thermostatic element 33. Thus, the hot melt adhesive in the tank can be maintained at a thermostatically controlled temperature.

The application or transfer roller 16 includes opposed radially extending faces 34 and 35 and a peripheral appli'- cation face or edge 36 which extends normal to the faces 34 and 35 and in an axial direction. The upper radial face 34 is provided with an annular relief portion 37 that extends at a point inwardly from the peripheral edge 36 to the hollow hub 38 for coacting with the doctor and scraper unit 17 to prevent build up of material on the roller. The hollow hub portion 38 extends normal to the radial faces 34 and 35 and centrally of the roller, and is fastened to the application roller shaft 39 by a pin 40.

The shaft 39 is beariugly mounted in a bracket 41 by means of bearings 42 and 43 supported in a bearing block 44. A spacer member 45 maintains the bearings 42 and 43 in spaced relation. The bracket 41 is secured to a cross bar 45 extending between the opposite side walls 18 and 19 of the tank. A pair o f capscrews or bolts 46 serve to removably fasten the bracket 41 to the cross bar 45.

The application roller shaft 39, is driven by a bevel gear 47 that is freely rotatable on the shaft and impositively connected thereto through a clutch member 48 that is keyed to the shaft. The clutch member 48 includes a hollow cylindrical sleeve portion 49 freely received over the shaft and keyed thereto, and a flange portion 50 that is provided with radially extending grooves 51 adapted to engage resiliently biased ball detents 52 mounted in the bevel gear 47. While any number of grooves and ball detents may be provided, it has been found that three are suflicient and which would be equally spaced apart. The clutch member 48. is also spring biased against the bottom of a bore 53 provided in the gear 47 by means of a coil spring 54. The coil spring 54 is bottomed at oney end against the auge 50 of the clutch member 48 and at the other end against a spring retainer 55 that is held in place by a capscrew 56 which is threadedly received in the end of the shaft 39. Thus, rotation of the bevel gear 4.7 will drive the shaft 39 through the clutch member 48 and the ball detents 52, unless an obstruction is met by the application roller 16.. Then the spring biased ball detent 52 and/or the spring biased clutch member 48 will permit slippage between the gear 47 and the clutch member 48 to prevent possible injury to the applicator. As seen particularly in FIG. 1, the bevel gear 47 may be driven by another bevel gear 57 mounted on a vertical shaft 58 and connected to a suitable power supply.

The doctor and scraper unit 17 includes generally a shaft 59 having a shoulder 60 formed thereon, a scraper blade assembly 61, a doctor blade 6,2 (FIG. 6), a lock nut 63 and a pointer 64. The shaft 59 extends through a bore 65 formed in the bracket 44 for rotation therewith and is provided with a threaded portion 66 and a wrench engaging portion 67 at the upper free end that extends above the bracket 44. The pointer 64 is keyed to the shaft to rotate therewith, and the lock nut 63 is received on the threaded portion 66 to bear down against the pointer and against the upper side of the bracket 44 to lock the doctor and scraper unit in adjusted position. As seen particularly in FIG. 7, graduation marks 68 may be provided on the top of the bracket 44 for determining the position of the doctor and scraper .unit as indicated by the pointer 64. When it is desired to change the position of the doctor and scraper unit, it is only necessary to release the lock nut 63 and apply a wrench to the portion 67 and turn the unit to the desired position. The shoulder 60 also serves to properly position the scraper assembly 61 relative to the application roller 16.

The lower end of the shaft 59 is notched to dene a semi-cylindrical portion 69 that defines at one edge the doctor blade 62 and which has mounted thereto by suitable fasteners the scraper assembly 61. The scraper assemblyV 61 includes upper and lower scrapers 70 and 71, respectively, engaging the upper and lower faces 34 and 35 of the application roller 16, and being integrally connected together by means of a web section 72 which is received in the notched portion or on the semi-cylindrical portion 69 of the shaft 59. The lower scraper 71 essentially ts between the lower face 35 of the roller and the upper section 24 of the front wall 22 and preventsthe roller from carrying material along the lower face 35 and the upper section 24. The scraper assembly 61 is therefore essentially notched to define the Scrapers 70 and 71, and the connecting edge 73 between the scrapers is arranged to be spaced back from the doctor blade 62. The doctor blade 62 may be variably spaced from the applying face 36 of the roller as above explained to control the thickness of the coating material on the applying face and therefore controlling the thickness of the coating applied to the carton flaps. v

A stationary scraper and doctor blade 74, secured to the upper section 24 by means of a capscrew 75,*FIG. 6, serves to additionally guard against the build up of coating material on the faces of the roller 16, and especially the lower radial face 35 and the outer peripheral applying face 36. This unit is arranged to have an edge 76 for scraping the Yface 35 and a doctor blade 77 for controlling the thickness of material on the applying face 36 The control is primarily accomplished by the doctor blade 62, and therefore the doctor blade 77 controls the thickness in the range above the range of the blade 62.

A cover member 78, FIGS. 1 and 2, is provided for covering the upper open end of the compartment 29, and is therefore provided with suitable openings to fit around the roller hub 38 and the doctor and scraper shaft 59, as

well as to provide an opening 79 through which the ap plication roller 16 extends. This cover member is loosely set in place on the tank and provided with anges for positioning same properly.

The applicator of the present invention can be easily adjusted to vary the thickness of coating to be applied to carton flaps as above indicated, and also `can be easily disassembled for cleaning purposes at the conclusion of an operational coating run. For example, the entire roller and doctor and scraper unit can be removed together since both are mounted on the bracket 44. Removal of the capscrews 46 allows removal of these units. so that they may be cleaned and also so that the interior of the tank may be reached for cleaning same. Further, the scraper assembly 61 may be easily removed from the shaft 59.

It will be understood that modifications and variations may be effected without departing from the scope of the novel concepts of the present invention, but it is understood that this application is to be limited only by the scope of the appended claims.

The invention is hereby claimed as follows:

1. A hot melt adhesive applicator for applying anV adhesive coating of predetermined thickness to a carton flap, said applicator comprising, a tank for holding a supply of molten hot melt adhesive, said tank including a bottom wall, vertical parallel opposed side walls, a rear vertical wall extending normal to the side walls, and a front wall having a lower section extending from the bottom wall and making an obtuse angle therewith, and an upper section extending angularly from the lower section away from the rear wall, a cross bar extending between the opposed side walls of the tank and parallel to said upper section, a bracket removably mounted on said cross bar, an application roller rotatably mounted on said cross bar having a portion extending deeply into the tank for immersion in a supply of adhesive and a portion extending outside of the tank beyond said upper section for engaging carton flaps, and a doctor blade and scraper unit mounted on :said bracket for controlling the adhesive thickness on the roller to be applied to the carton flaps and for removing adhesive from other parts of the roller 2. A hot melt adhesive applicator for applying an adhesive coating of predetermined thickness to a carton ap, said applicator comprising, a tank for holding a supply of molten hot melt adhesive, said tank including a bottom wall, vertical parallel opposed side walls, a rear vertical wall extending normal to the side walls, and a front wall having a lower section extending from the bottom wall and making an obtuse angle therewith, and an upper section extending angularly from the lower section away from the rear wall, a cross bar extending between the opposed side walls of the tank and parallel to said upper section, a bracket removably mounted on said cross bar, a disc-shaped application roller having opposed radial faces and an axially extending peripheral adhesive applying face, a shaft supporting said roller and being rotatably mounted on said bracket so that the disc rotates through a plane parallel to said upper section and wherein the disc will be partially immersed in the adhesive supply and partially extend outward of the tank to coat carton aps, and a doctor blade and scraper unit mounted on said bracket for gauging the thickness of adhesive on the applying face just prior to application and for removing adhesive from the radial faces.

3. A hot melt adhesive applicator for applying an adhesive coating of predetermined thickness to a carton ap, said applicator comprising, a tank for holding a supply of molten hot melt adhesive, said tank including a bottom wall, vertical parallel opposed side walls, a rear vertical wall extending normal to the side walls, and a front wall having a lower section extending from the bottom Wall and making an obtuse angle therewith, and an upper section extending angularly from the lower section away from the rear wall, a cross bar extending between the opposed side walls of the tank and parallel to said upper section, a bracket removably mounted on said cross bar, a disc-shaped application roller having opposed radial faces and an axially extending peripheral adhesive applying face, a shaft supporting said roller and being rotatably mounted on said bracket so that the disc rotates through a plane parallel to said upper section and wherein the disc will be partially immersed in the adhesive supply and partially extend outward of the tank to coat carton aps, a rod mounted on said bracket parallel to said roller shaft, a doctor blade on said rod arranged adjacent the adhesive applying face for doctoring the adhesive thereon to control the thickness to be applied to the carton aps, and Scrapers mounted on said rod to remove adhesive from the radial faces of the roller.

4. The combination as dened in claim 2, wherein a relief is provided in the upper radial face of the roller.

5. A hot melt adhesive applicator for applying an adhesive coating of predetermined thickness to a carton ap, said applicator comprising, a tank for holding a supply of molten hot melt adhesive, said tank including a bottom wall, vertical parallel opposed side Walls, a rear vertical wall extending normal to the side walls, and a front wall having a lower section extending from the bottom wall and making an obtuse angle therewith, and an upper section extending angularly from the lower section away from the rear wall, a `cross bar extending between the opposed side walls of the tank and parallel to said upper section, a bracket removably mounted on said cross bar, a disc-shaped application roller having opposed radial faces and an axially extending peripheral adhesive applying face, a shaft supporting said roller and being rotatably mounted on said bracket so that the disc rotates through a plane parallel to said upper section and wherein the disc will be partially immersed in the adhesive supply and partially extend outward of the tank to coat carton flaps, a rod adjustably mounted on said bracket and extending parallel to said roller shaft, a doctor blade on said rod arranged adjacent the adhesive applying face for doctoring the adhesive thereon to control the thickness to be applied to the carton flaps, and Scrapers mounted on said rod to remove adhesive from the radial faces of the roller.

6. A hot melt adhesive applicator for applying an adhesive coating of predetermined thickness to a carton flap, said applicator comprising, a tank for holding a supply of molten hot melt adhesive, said tank including a bottom wall, vertical parallel opposed side walls, a rear vertical wall extending normal to the side walls, and a front wall having a lower section extending from the bottom wall and making an obtuse angle therewith, and an upper section extending angularly from the lower section away from the rear wall, a cross bar extending between the opposed side walls of the tank and parallel to said upper section, a bracket removably mounted on said cross bar, a disc-shaped application roller having opposed radial faces and an axially extending peripheral adhesive applying face, a shaft supporting said roller and being rotatably mounted on said bracket so that the disc rotates through a plane parallel to said upper section and wherein the disc will be partially immersed in the adhesive supply and partially extend outward of the tank to coat carton flaps, a rod adjustably mounted on said bracket and extending parallel to said roller shaft, a doctor blade on said rod arranged adjacent the adhesive applying fa for doctoring the adhesive thereon to control the thickness to be applied to the carton flaps, and Scrapers mounted on said rod to remove adhesive from the radial faces of the roller, said doctor blade and scrapers being positioned above the adhesive supply.

7. The combination as defined in claim 6, wherein a stationary doctor blade and scraper is mounted on said upper section to coact with the adhesive applying face and the lower radial face.

8. The combination as dened in claim 2, and a drive gear freely rotatable on said shaft and clutchingly coupled thereto.

References Cited UNITED STATES PATENTS 882,251 v 3/1908 Knope 118-261 2,200,417 5/1940 Doyle 118-261 2,397,853 4/ 1946 Gist 118-261 2,693,429 10/ 1954 Radike et al. 118-262 3,001,505 9/1961 Novick 118-244 CHARLES A. WILLMUTH, Primary Examiner. R. I. SMITH, Assistant Examiner. 

1. A HOT MELT ADHESIVE APPLICATOR FOR APPLYING AN ADHESIVE COATING OF PREDETERMINED THICKNESS TO A CARTON FLAP, SAID APPLICATOR COMPRISING, A TANK FOR HOLDING A SUPPLY OF MOLTEN HOT MELT ADHESIVE, SAID TANK INCLUDING A BOTTOM WALL, VERTICAL PARALLEL OPPOSED SIDE WALLS, A REAR VERTICAL WALL EXTENDING NORMAL TO THE SIDE WALLS, AND A FRONT WALL HAVING A LOWER SECTION EXTENDING FROM THE BOTTOM WALL AND MAKING AN OBTUSE ANGLE THEREWITH, AND AN UPPER SECTION EXTENDING ANGULARLY FROM THE LOWER SECTION AWAY FROM THE REAR WALL, A CROSS BAR EXTENDING BETWEEN THE OPPOSED SIDE WALLS OF THE TANK AND PARALLEL TO SAID UPPER SECTION, A BRACKET REMOVABLY MOUNTED ON SAID CROSS BAR, AN APPLICATION ROLLER ROTATABLY MOUNTED ON SAID CROSS BAR HAVING A PORTION EXTENDING DEEPLY INTO THE TANK FOR IMMERSION IN A SUPPLY OF ADHESIVE AND A PORTION EXTENDING OUTSIDE OF THE TANK BEYOND SAID UPPER SECTION FOR ENGAGING CARTON FLAPS, AND A DOCTOR BLADE AND SCRAPER UNIT MOUNTED ON SAID BRACKET FOR CONTROLLING THE ADHESIVE THICKNESS ON THE ROLLER TO BE APPLIED TO THE CARTON FLAPS AND FOR REMOVING ADHESIVE FROM OTHER PARTS OF THE ROLLER. 